How much RAM are you running off of? If it's less than 2GB than the odds are your computer just can't handle the extra oomph needed for Minecraft + mods.
It's doubtful the files exist in loose file format, and it's even less likely that an uninstaller (Windows or Revo) could work from them.
New tactic: Install the latest version of 64-bit Java 7 here. After that's installed, use the following directions to attempt to set up a new default Java...
Random idea: Download the .jar of the launcher, right click it, and select "Open With:". Navigate to your Java 7 folder (mine's in C:\Program Files\Java\jre7\bin) and selected java.exe. See if the launcher runs when it's told which executable to latch onto.
Ender chests are known issues right no, CodeChickenCore stuff. Should be fixed in next update by Chicken. Sorry for the crash, best to avoid them for now. =) Same with bags!
Yeah, I figured that cycle would happen. Their installer package (as with most) is linked to uninstall as well. Sad.
Give this a whirl to uninstall ALL Java programs (then install only 7 32/64-bit, whichever you have).
I believe Meldiron was just seeing if it was an access issue.
Having Java 6 and 7 is likely the culprit here. What happens when you try to uninstall Java 6, again? It asks for a .dll for the uninstall?
Open that hosts file in notepad and make sure session.minecraft.net (or something like that) is not present. If it is, delete that entire line and try again.
Did you check Programs and Features to see exactly which versions of Java are installed?